JP3064321B2 - Surface acoustic wave filter - Google Patents
Surface acoustic wave filterInfo
- Publication number
- JP3064321B2 JP3064321B2 JP2050898A JP5089890A JP3064321B2 JP 3064321 B2 JP3064321 B2 JP 3064321B2 JP 2050898 A JP2050898 A JP 2050898A JP 5089890 A JP5089890 A JP 5089890A JP 3064321 B2 JP3064321 B2 JP 3064321B2
- Authority
- JP
- Japan
- Prior art keywords
- acoustic wave
- surface acoustic
- wave filter
- electrode
- terminal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000010897 surface acoustic wave method Methods 0.000 title claims description 9
- 239000000758 substrate Substances 0.000 claims description 7
- 230000005684 electric field Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は弾性表面波フィルタに関し、特に重み付け交
叉指状電極を配設した弾性表面波フィルタに関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave filter, and more particularly, to a surface acoustic wave filter provided with weighted interdigital electrodes.
従来の弾性表面波フィルタは、第２図に示すように、
圧電基板状に重み付けを施された交叉指状電極21,24を
長さ方向に並行配列した構造を有し、両者の交叉部S1〜
S7の大小で重み付け量を設定している。交叉指状電極2
1,24はそれぞれ、ホット側端子１、設置に接続したバス
バー12,13に接続されている。A conventional surface acoustic wave filter is, as shown in FIG.
It has a structure in which interdigitated electrodes 21, 24 weighted in a piezoelectric substrate shape are arranged in parallel in the length direction, and the intersecting portions S1 to
The weighting amount is set according to the magnitude of S7. Cross finger electrode 2
1, 24 are connected to the hot side terminal 1 and the bus bars 12, 13 connected to the installation, respectively.
上述した従来の弾性表面波フィルタでは、交叉部S1〜
S7がバスバー12,13間の中央近傍に分布しており、そこ
までホット側の交叉指状電極21を伸ばして配設せねばな
らず、交叉指状電極21の総面積が広くなり、これに伴な
って基板の厚さ方向の電界により励振される不要波の影
響が増大し、帯域内のフィルタ特性にリップルを生じて
しまうという欠点がある。In the above-described conventional surface acoustic wave filter, the crossing portions S1 to
S7 is distributed in the vicinity of the center between the busbars 12 and 13, and the hot-side interdigital electrodes 21 must be extended and arranged to that extent, and the total area of the interdigital electrodes 21 increases, Accompanying this, there is a disadvantage that the influence of unnecessary waves excited by the electric field in the thickness direction of the substrate increases, causing ripples in the filter characteristics in the band.
本発明の弾性表面波フィルタは、圧電基板上に重み付
けを施された交叉指状電極を有し、ホット側端子および
接地側端子にそれぞれ接続した１対のバスバーをもつ弾
性表面波フィルタにおいて、前記接地側端子に接続した
バスバーに連なる複数の交叉指状電極のうちの選ばれた
交叉指状電極は折れ曲がり形状を有して前記ホット側端
子に接続したバスバーに連なる交叉指状電極の先端より
ホット側端子側に離間した箇所において前記重み付けの
割合をあらわす前記交叉指状電極の交叉部を形成し、こ
れによりこの交叉部を、一対の前記バスバーのうちホッ
ト側端子に接続した一方に近接させて配置した構成を有
する。The surface acoustic wave filter of the present invention has a weighted interdigital electrode on a piezoelectric substrate, and has a pair of bus bars connected to a hot terminal and a ground terminal, respectively. The selected cross finger electrode of the plurality of cross finger electrodes connected to the bus bar connected to the ground terminal has a bent shape and is hotter than the tip of the cross finger electrode connected to the bus bar connected to the hot side terminal. Forming a crossing portion of the cross finger-like electrode that represents the weighting ratio at a position separated from the side terminal side, thereby bringing this crossing portion close to one of the pair of bus bars connected to the hot side terminal. It has a configuration in which it is arranged.
次に、本発明について図面を参照して説明する。 Next, the present invention will be described with reference to the drawings.
第１図は本発明の一実施例の平面図である。圧電基板
上の、重み付けを施した交叉指状電極11,14の重み付け
量をあらわす交叉部S1〜S6は、ホット側の端子１に接続
したバスバー12の方に近付けて配置されており、接地し
たバスバー13に接続する交叉指状電極14を交叉部S1〜S6
まで伸ばして配設してある。このように配列することに
より、ホット側の交叉指状電極11の長さは従来よりも短
縮できる。従って、ホット側の端子１に接続する交叉指
状電極１の総面積を最小にして、基板の厚み方向の電界
により励振される不要波の影響を従来よりも抑圧でき
る。FIG. 1 is a plan view of one embodiment of the present invention. The crossover portions S1 to S6 indicating the weighting of the weighted cross finger electrodes 11 and 14 on the piezoelectric substrate are disposed closer to the bus bar 12 connected to the terminal 1 on the hot side, and are grounded. The cross finger electrodes 14 connected to the bus bars 13 are connected to the cross portions S1 to S6.
It is stretched out and arranged. By arranging in this way, the length of the interdigital electrode 11 on the hot side can be shortened as compared with the related art. Therefore, the total area of the interdigital electrodes 1 connected to the terminals 1 on the hot side can be minimized, and the influence of unnecessary waves excited by the electric field in the thickness direction of the substrate can be suppressed as compared with the related art.
以上説明したように本発明では、重み付けを施した交
叉指状電極の各交叉部をホット端子に近付けて配設する
ことにより、ホット端子に接続する交叉指状電極の総面
積を最小化でき、基板の厚さ方向の電界により励振され
る不要波を抑圧できるので、帯域内のリップルを低く抑
えられ高性能なフィルタを実現できる。As described above, in the present invention, by arranging each crossing portion of the weighted cross-finger electrode close to the hot terminal, the total area of the cross-finger electrode connected to the hot terminal can be minimized. Since unnecessary waves excited by the electric field in the thickness direction of the substrate can be suppressed, ripples in the band can be suppressed low, and a high-performance filter can be realized.
第１図は本発明の一実施例を示す平面図、第２図は従来
の弾性表面波フィルタを示す平面図である。 １……端子、11,14,21,24……交叉指状電極、12,13……
バスバー、S1〜S7……交叉部。FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is a plan view showing a conventional surface acoustic wave filter. 1 ... Terminals, 11,14,21,24 ... Cross-finger electrodes, 12,13 ...
Bus bar, S1 ~ S7 …… Cross section.
Claims (1)
電極を有し、ホット側端子および接地側端子にそれぞれ
接続した１対のバスバーをもつ弾性表面波フィルタにお
いて、前記接地側端子に接続したバスバーに連なる複数
の交叉指状電極のうちの選ばれた交叉指状電極は折れ曲
がり形状を有して前記ホット側端子に接続したバスバー
に連なる交叉指状電極の先端よりホット側端子側に離間
した箇所において前記重み付けの割合をあらわす前記交
叉指状電極の交叉部を形成し、これによりこの交叉部
を、一対の前記バスバーのうちホット側端子に接続した
一方に近接させて配置した構成を有することを特徴とす
る弾性表面波フィルタ。1. A surface acoustic wave filter having a weighted interdigital electrode on a piezoelectric substrate and having a pair of bus bars connected to a hot terminal and a ground terminal, respectively. The selected cross finger electrode of the plurality of cross finger electrodes connected to the connected bus bar has a bent shape and is closer to the hot side terminal than the tip of the cross finger electrode connected to the bus bar connected to the hot side terminal. A configuration in which a crossing portion of the cross finger-like electrode representing the weighting ratio is formed at a separated location, and this crossing portion is arranged close to one of the pair of bus bars connected to the hot side terminal. A surface acoustic wave filter comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2050898A JP3064321B2 (en) | 1990-03-02 | 1990-03-02 | Surface acoustic wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2050898A JP3064321B2 (en) | 1990-03-02 | 1990-03-02 | Surface acoustic wave filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03253110A JPH03253110A (en) | 1991-11-12 |
| JP3064321B2 true JP3064321B2 (en) | 2000-07-12 |
Family
ID=12871563
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2050898A Expired - Fee Related JP3064321B2 (en) | 1990-03-02 | 1990-03-02 | Surface acoustic wave filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3064321B2 (en) |
-
1990
- 1990-03-02 JP JP2050898A patent/JP3064321B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03253110A (en) | 1991-11-12 |
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| LAPS | Cancellation because of no payment of annual fees |